Apparatus and method of optical disk recording while detecting vibration

ABSTRACT

According to the present invention, it is intended that the recording can be executed normally even against small vibrations to which a servo error signal detecting circuit cannot respond. A recording apparatus according to the present invention includes an optical head ( 12 ) for receiving a reflected laser beam (LREF) obtained when a laser beam (LIRR) is irradiated on a CD-R ( 10 ). This recording apparatus further includes a gate circuit ( 31 ) to which an output signal (SRD) of the optical head ( 12 ) is supplied and a level comparing circuit ( 34 ) for comparing a value of an output signal (DTAU) of this gate circuit ( 31 ) with a predetermined reference value (DTH). Upon recording, the gate circuit ( 31 ) is controlled in such a manner that a signal of a predetermined period ts may be outputted from the output signal (SRD) supplied from the optical head ( 12 ) to the gate circuit ( 31 ) as the output signal (DTAU). An output signal (SCMP) of the level comparing circuit ( 34 ) is outputted as a detected result of vibrations of the CD-R ( 10 ) or vibrations of the optical head ( 12 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.10/182,867, filed on Oct. 8, 2002, now U.S. Pat. No 7,038,980 thedisclosure of which is hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a recording apparatus for and arecording method of recording a signal on a disk by using a laser beam.

BACKGROUND ART

Disks on which a signal can be recorded by using a laser beam are nowavailable. A CD-R is known as one of such disks on which a signal can berecorded by using a laser beam. In this case, a CD-R is required to haveread-out characteristics which are equivalent to those of a CD. Then, aCD is designed to record a signal by a combination of portions (called“lands”) in which the amount of light of a reflected laser beam isincreased when it is irradiated by a laser beam and portions (called“pits”) in which the amount or light of a reflected laser beam isdecreased when it is diffracted.

Therefore, the CD-R is provided with, as a recording layer, a dye layerhaving a high reflectance of a laser beam and which corresponds to theland. When this dye layer is irradiated by a laser beam, the dye layergenerates heat from its point at which it is irradiated by a laser beamand thereby this point is deformed. This deformed portion has areflectance lower than that of the dye layer and becomes a pit.Accordingly, the intensity of a laser beam is modulated by a recordingsignal, whereby the recording signal can be recorded on the CD-R.

In this case, however, since the dye layer produces intensive heat withthe irradiation of the laser beam and thereby the recording signal canbe recorded, the laser beam should be focused on the dye layer with highaccuracy. Moreover, the position at which the CD-R is irradiated by thelaser beam has to be prevented from being displaced from a track.However, when a CD-R or a recording and reproducing optical head(optical pickup) is vibrated, it is unavoidable that theproperly-focused state of the laser beam is broken or that the trackposition (position irradiated by a laser beam) is displaced.

To solve this problem, a recording apparatus in actual practice isprovided with a laser beam focusing and tracking servo system.Therefore, when vibrations to the CD-R or to the optical head are not solarge, this servo system may respond to such vibrations to therebycontrol the optical head in such a manner that the optical head canescape from the influence exerted by such vibrations. Thus, a recordingsignal can be recorded on the disk normally. Further, when vibrationsare so large that the optical head becomes unable to continue therecording, the recording made by the optical head is stopped for amoment. At the same time, when the vibrations are removed, if therecording is resumed from where the recording was stopped on the disk,then a recording signal can be recorded on the disk normally.

However, even when vibrations are small enough to cause the servo systemto respond to such small vibrations normally, it is unavoidable that alaser beam is not properly focused or that a tracking error occurs dueto the reasons which will follow. As a consequence, it is frequentlyobserved that a recording signal cannot be recorded on the CD-Rsatisfactorily.

That is, the influences exerted upon the recording layer of the CD-R byvibrations generally exist in both of the focusing direction and thetracking direction. However, when the vibrations are displaced in onedirection of either the focusing direction or the tracking direction,since the level of an error component (error component produced due tovibrations) contained in a focusing servo signal or a tracking servosignal reaches a certain level, the level of the error component can bedetected and the recording can be stopped.

However, even when vibrations are of the same magnitude, if vibrationcomponents are dispersed into both of the focusing direction and thetracking direction, then individual vibration components become smallwith the result that error components (error components produced due tovibrations) contained in the focusing servo signal and the trackingservo signal reach very small values, respectively. In addition, afocusing error signal and a tracking error signal contain errorcomponents produced due to an eccentricity or disk skew of the CD-R.

For this reason, when the vibration components are dispersed into thefocusing direction and the tracking direction, it is very difficult todetect the error components produced due to the vibrations. Therefore,there is a semblance as if the recording of the recording signal on thedisk was ended normally.

As described above, even with such small vibrations, it is unavoidablethat there occurs a slight displacement of a focus or a very smalltracking error. As a result, the recording signal cannot be recorded onthe CD-R satisfactorily.

Therefore, in order to cope with such situations, as is disclosed in aJapanese laid-open patent application No. 2000-90448, for example, ithas so far been proposed that a recording apparatus be provided with avibration detecting sensor capable of detecting the vibrations on theoutside of the optical head and the CD-R. According to this method,however, since vibrations at the very portion that is performing arecording can not be necessarily being detected, vibrations which areharmful for the recording cannot always be detected, and a user tends tofail in the recording of the recording signal on the disk accordingly.

Then, in the case of a digital camera using a CD-R as a recordingmedium, when such digital camera fails to record an image signal,because the digital camera is unable to recapture the image signal to berecorded, there should be no excuse for failing in the recording.

On the other hand, when recording signals to be recorded on the CD-R arethose obtained from other suitable media or equipment such as CDs orcomputers, even if a user fails in the recording, then a signal to berecorded on the disk can be obtained again, and hence a user is able torecord the recording signal on the disk once more. However, until allrecorded materials are played back thoroughly, a user is unable todetermine whether or not the first recording has been made normally.Therefore, checking of whether or not the recording signal has beenrecorded on the disk normally takes a user a lot of time.

It is an object of the present invention to solve the aforementionedproblems.

DISCLOSURE OF INVENTION

According to the present invention, there is provided a recordingapparatus for recording a signal on a disk by irradiating a laser beamon the disk. This recording apparatus is comprised of a photoreceptorfor receiving a reflected laser beam obtained when the laser beam isirradiated on the disk, a gate circuit to which a signal outputted fromthe photoreceptor is supplied and a level comparing circuit forcomparing a value of the output signal from the gate circuit with apredetermined reference value, wherein upon recording, the gate circuitis controlled in synchronism with the signal to be recorded in such amanner that it may derive, as an output signal, a signal of apredetermined period from among the output signals supplied from thephotoreceptor to the gate circuit and an output signal of the levelcomparing circuit is derived as a result of detecting vibrations of thedisk or vibrations of a light source for outputting the laser beam.

Therefore, it can be detected based upon the detected result of thevibrations whether or not the pits are formed on the disk in actualpractice.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a recording apparatus recording andreproducing apparatus) according to an embodiment of the presentinvention.

FIG. 2 is a diagram of waveforms for explaining the present invention.

FIG. 3 is a diagram of waveforms for explaining the present invention.

FIG. 4 is a diagram of waveforms explaining the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

A best mode for carrying out the invention will be described below withreference to the drawings.

First, a relationship between a recording signal supplied to an opticalpickup and a signal obtained from the optical pickup upon recording willbe described with reference to FIG. 2.

FIG. 2A shows an example of a recording signal SWRT. This recordingsignal SWRT is an EFM signal the level of which takes two values of “0”and “1” and whose pulse width TW varies in response to recordedcontents.

Then, a recording current is supplied to a laser diode of an opticalhead (optical pickup) in proportion to this recording signal SWRT,whereby the optical head outputs irradiated laser beam LIRR whichcorresponds to the recording signal SWRT and whose amount of lightvaries at a leading edge time ts and at a trailing edge time te of therecording signal SWRT as shown in FIG. 2B. However, at that time, sincea direct current bias is added to the recording current that is suppliedto the laser diode of the optical head, the amount of light of theirradiated laser beam LIRR from the laser diode is held at apredetermined value BRD even when the recording signal SWRT is held atlow “0” level.

This predetermined value BRD has a magnitude to the extent that arecording signal cannot be recorded on the CD-R. This predeterminedvalue is selected to be equal to the amount of light required when asignal is read out from the CD-R. The amount of light BWRT of theirradiated laser beam LIRR obtained when the recording signal SWRT isheld at high “1” level is approximately 50 times, for example, as largeas the amount of light BRD which is used to read out a signal from thedisk.

When the irradiated laser beam LIRR from this optical head is irradiatedon a dye layer (recording layer) of the CD-R, part of the irradiatedlaser beam is reflected from the dye layer (recording layer) andreflected laser beam LREF is received by the same optical head. When arecording signal is recorded on the disk normally, the amount of lightof the reflected laser beam LREF varies as shown in FIG. 2C.Specifically, since the amount of light of the irradiated laser beamLIRR is held at the small value BRD until the leading edge time ts ofthe recording signal SWRT, the amount of light of the reflected laserbeam LREF is held at a small value CRD.

Then, when the recording signal SWRT rises up to high “1” level at thetime ts, since the amount of light of the irradiated laser beam LIRR isheld at the large value BWRT, the dye layer of the CD-R starts toproduce heat from a point irradiated by the irradiated laser beam LIRR.However, since the irradiated point on the dye layer has yet to bedeformed immediately after the time ts, the amount of light of thereflected laser beam LREF increases considerably in response to theamount of light BWRT of the irradiated laser beam LIRR and becomesmaximum.

However, since the irradiated point on the dye layer of the CD-R startsto produce heat and begins to be deformed by irradiation of theirradiated laser beam LIRR, when this irradiated point on the dye layeris deformed, the amount of light of the reflected laser beam LREFdecreases progressively. Then, at a certain time ta, the deformation ofthe irradiated point on the dye layer due to the produced heat reachesthe limit with the result that the amount of light of the reflectedlaser beam LREF is continuously held at the value Ca after the time ta.

At the trailing edge time ts of the recording signal SWRT, the amount oflight of the irradiated laser beam LIRR is held at the small value BRDso that the amount of light of the reflected laser beam LREF is returnedto the value CRD. Thereafter, the amount of light of that reflectedlaser beam is continuously held at the value CRD.

Then, since the reflected laser beam LREF varies as shown in FIG. 2C,the optical head produces an output signal SRD whose level DRDcorresponds to the amount of light of the reflected laser beam LREF asshown in FIG. 2D. Specifically, because the amount of light of thereflected laser beam LREF is held at the value CRD before the leadingedge time ts and after the trailing edge time te, the level of theoutput signal SRD also is held at the value DRD. The output signal SRDis held at the value DRD as described above even during the period inwhich the recording signal SWRT is held at low “0” level, and hence thefocusing servo and the tracking servo required upon recording can becarried out by using this output signal.

During the period ranging from the time ts to the time ta, the level ofthe output signal SRD suddenly reaches the maximal value as the amountof light of the reflected laser beam LREF varies and is then gentlylowered to the value Da. Then, the level of this output signal is heldat substantially the value Da during the period ranging from the time tato the time te (=τ).

At a time of actual recording, since the recording signal SWAT variescontinuously between the low “0” level and the high “1” level and thepulse width TW of this recording signal varies in response to therecorded contents as shown in FIG. 3A, for example, the output signalSRD also varies in response to the recording signal SWRT as shown inFIG. 3B.

In this case, if the recording signal is recorded on the disk normally,then the variation characteristics of the reflected laser beam LREFduring the period ranging from the time ts to the time ta are nearlyconstant. Thus, even when the pulse width TW of the recording signalSWRT varies, the duration of the period ranging from the time ts to thetime ta is nearly constant. Then, the pulse width TW of the recordingsignal SWRT varies in response to the recorded contents. Therefore, theperiod τ (=period ranging from the time ta to the time te) at theconstant level varies in response to the contents of the recordingsignal SWRT.

When a CD-R in which a recording signal has been recorded normally isplayed back the dye layer of the disk at its portion corresponding tothe period TW (in particular, the period τ) is deformed and hence theamount of light of the reflected laser beam LREF is decreasedaccordingly. Consequently, as illustrated and also shown in FIG. 3, theportion corresponding to the period τ is formed as a pit (P). Becausethe dye layer of the remaining portion is not deformed, the amount oflight of the reflected laser beam LREF is large and hence the remainingportion is formed as a land (L). That is, when the recording signal SWRTis held at high level “1”, the pits are formed.

So far we have described the case in which the recording signal isrecorded on the disk normally. When the irradiated laser beam LIRR isnot properly focused or the tracking is displaced due to the vibrationsof the disk, the irradiated point on the dye layer does not produceintensive heat sufficiently and this irradiated point cannot be deformedsatisfactorily.

As a consequence, the amount of light of the reflected laser beam LREFvaries as shown in FIGS. 4B, 4C or FIG. 4D so that it can be preventedfrom being lowered to the original amount of light Ca. Therefore, theoutput signal SRD from the optical head varies as does the amount oflight shown in FIGS. 4B, 4C or FIG. 4D and can be prevented from beinglowered to the original level Da.

Although the amount of light of the reflected laser light LREF isdecreased a little when the irradiated laser beam LIRR is not properlyfocused, the decreased amount of light of this reflected laser beam isconsiderably small as compared with the case in which the amount oflight of the reflected laser beam is decreased due to the existence ofthe pits and this decreased amount of light is made negligible.

According to the present invention, having noticed the fact that theoutput signal SRD outputted from the optical head upon recording variesas described above when the recording signal is recorded normally on thedisk or the recording signal is not recorded normally on the disk, thereare provided a recording apparatus and a recording method by which thefact that the irradiated laser beam LIRR is not properly focused or thatthe tracking is displaced due to the vibrations of the disk or theoptical pickup can be directly detected from the output signal SRD.

An example in which the present invention is applied to a recording andreproducing apparatus using a CD-R as a recording medium willhereinafter be described with reference to FIG. 1.

Referring to FIG. 1, there is provided a CD-R 10. This CD-R 10 isrotated at predetermined velocity by a spindle motor 11. An optical head(optical pickup) 12 is disposed in an opposing relation relation to thesignal recording surface of the CD-R 10. This optical head 12 can bemoved along the radius direction of the CD-R 10 by a sled motor 13 and asled shaft 14.

In this case, the optical head 12 is adapted to irradiate the laser beamLIRR on the CD-R 10 and to receive the reflected laser beam LREF fromthe disk. To this end, although not shown, this optical head includes alaser diode for converting the recording signal SWRT to provide theirradiated laser beam LIRR, a photodiode for receiving the reflectedlaser beam LREF and converting this reflected laser beam to provide theoutput signal SRD and optical systems for the laser beams LIRR, LREF.Further, this optical head 12 includes mechanisms for properly focusingand tracking the laser beams IRRR, LREF.

There is shown a recording and reproducing circuit 21. In thisembodiment, this recording and reproducing circuit 21 is comprised of anIC called a “CD-R processor”. Upon recording, this recording andreproducing circuit 21 converts digital data to be recorded to providean EFM signal, i.e., the recording signals SWRT by effecting a varietyof encode processings on recorded digital data (D) such as digital audiodata. Further, upon reproducing, the recording and reproducing circuit21 outputs the original data (D) by effecting a decode processing, whichis a processing complementary to that in the recording mode, on theoutput signal SRD obtained from the optical head 12.

Furthermore, the recording and reproducing circuit 21 forms and outputsservo signals for effecting a variety of servo control operations uponrecording and reproducing. In this embodiment, the recording andreproducing circuit 21 includes an A/D converter circuit 211 forconverting the output signal SRD into the digital signal SRD in the formof an analog-to-digital signal.

There is shown a control circuit 22. This control circuit 22 iscomprised of a microcomputer, for example, and is adapted to controlvarious items, such as the entire operation of this recording andreproducing apparatus or the tracking positions of the optical head 12required upon recording and reproducing.

Then, upon recording, the digital data (D) is supplied to the recordingand reproducing circuit 21 and thereby converted into the recordingsignal SWRT. This recording signal SWRT is supplied through a driveamplifier 23 to the optical head 12 and thereby converted into theirradiated laser beam LIRR. This irradiated laser beam LIRR isirradiated on the CD-R 10 and thereby a recording signal is recorded onthis disk.

At that time, the reflected laser beam LREF from the CD-R 10 is receivedby the optical head 12 and thereby outputted as the output signal SRD.This output signal SRD is supplied through an RF amplifier 24 to the A/Dconverter circuit 211 in the recording and reproducing circuit 21 andthereby converted into the digital signal SRD in the form of an analogto digital signal.

Then, further, the recording and reproducing circuit 21 forms a varietyof servo signals from the digital signal SRD, and these servo signalsare supplied to a drive circuit 25. Of these servo signals, a spindleservo signal is supplied to the spindle motor 11 and thereby arotational speed of the spindle motor is controlled. Thus, the linearvelocities at the recording/reproducing positions of the CD-R 10 can bemade constant.

A focusing servo signal is outputted from the drive circuit 25. Thisfocusing servo signal is supplied to the optical head 12 and thereby theirradiated laser beam LIRR can be properly focused underfocus-servo-control. Further, a sled servo signal and a tracking servosignal are outputted from the drive circuit 25. These sled servo signaland tracking servo signal are supplied to the sled motor 13 and theoptical head 12 and thereby the irradiated laser beam LIRR can besled-servo controlled and tracking-servo controlled.

On the other hand, upon reproducing, the output signal SRD of theoptical head 12 is supplied to the recording and reproducing circuit 21and thereby the above-mentioned servo-control-operations can beexecuted. Then, the recording and reproducing circuit 21 outputs theoriginal digital data (D) by effecting a reproducing decode processingon the output signal SRD from the A/D converter circuit 211.

Then, according to the present invention, in order to prevent theirradiated laser beam LIRR from being focused improperly and to preventthe tracking position from being displaced due to the above-mentionedvibrations upon recording, the recording and reproducing apparatus isfurther constructed as follows.

Specifically, as shown in FIG. 2, for example, since the recordingsignal SWRT is formed by the recording and reproducing circuit 21, therecording and reproducing circuit 21 can learn the leading edge time tsand the trailing edge time te of the recording signal SWRT. Further,since the period ranging from the time ts to the time ta is nearly madeconstant, the recording and reproducing circuit 21 can learn thestarting time ta of the flat period τ. Therefore, the recording andreproducing circuit 21 can learn the time position of this flat periodτ. Then, the control circuit 22 can learn the time position of this flatperiod τ.

To this end, the recording and reproducing apparatus shown in FIG. 1 isprovided with a gate circuit 31, an integrating circuit 32, a holdcircuit 33 and a level comparing circuit 34. In the case of therecording and reproducing apparatus shown in FIG. 1, however, thesecircuits 31 to 34 may be realized by the microcomputer comprising thecontrol circuit 22 and software that may be executed by themicrocomputer. FIG. 1 shows the circuits 31 to 34 thus realized from ahardware standpoint equivalently.

Then, upon recording, the digital output signal SRD from the A/Dconverter circuit 211 is supplied to the gate circuit 31 and the flatperiod τ of the digital output signal SRD is supplied from the recordingand reproducing circuit 21 to the microcomputer 22. Accordingly, a valueDTAU of the flat period τ of the signal SRD is outputted from the gatecircuit 31 in synchronism with each of the flat periods τ. This valueDTAU is compared with a reference value DTH in level by the levelcomparing circuit 34.

In a method of forming this reference value DTH, as will be describedlater on, when a recording signal is recorded on the disk normally (forexample, in the case of FIG. 3), the value DTAU of the signal SRD of theflat period τ becomes equal to a value Da. When the irradiated laserbeam LIRR is not properly focused and the tracking is displaced due tothe vibrations (for example, in the case of FIG. 4), the value DTAU ofthe signal SRS in the period τ becomes larger than the value Da.

Thus, we have the following equality:DTH=Da+ΔDIn this equation, ΔD represents the predetermined allowable error. Then,the level comparing circuit 34 outputs in every flat period τ a comparedoutput signal SCMP which goes to low “0” level when an inequality ofDTAU≦DTH is satisfied (for example, in the case of FIG. 3) and whichgoes to high “1” level when an inequality of DTAU>DTH is satisfied (forexample, in the case of FIG. 4). This compared output signal SCMP issupplied to the recording and reproducing circuit 21 as a control signalfor permitting/inhibiting the recording. When an equality of SCMP=“0” issatisfied, for example, the recording on the CD-R 10 may be permitted.When an equality of SCMP=“1” is satisfied, the recording on the CD-R 10may be inhibited. When the equality of SCMP=“0” is satisfied after therecording is inhibited, the recording may be resumed from the signalSWRT obtained at the time in which the recording is inhibited.

The manner in which the reference value DTH of the level comparingcircuit 34 is formed by the recording and reproducing apparatus shown inFIG. 1 will be described below. Specifically, when the recording isstarted, the value DTAU of the flat period τ of the digital outputsignal SRD is outputted from the gate circuit 31 in every period τ overone to several frame periods. This value DTAU is supplied to andintegrated by the integrating circuit 32, and an integrated value DINTis held by the hold circuit 33.

In this case, the value DINT is an average value of the flat period τ inone to several frame periods. Then when one to several frame periods areaveraged, the influences of noises produced by dusts or scratches aremade negligible. Accordingly, the value DINT held by the hold circuit 33may be corrected by only the magnitude of the allowable error ΔD andsupplied to the comparing circuit 34 as the reference value DTH, inwhich it may be used to compare the two levels as described above.

In this manner, according to the above-mentioned recording andreproducing apparatus, when the irradiated laser beam LIRR is notproperly focused and the tracking is displaced due to the vibrations,such defocused state and displacement of the tracking can be detected.Then, in this case, according to the present invention, since it isdetected by checking the amount of light of the reflected laser beamLREF in the flat period τ whether or not the pits are formed in actualpractice, even vibrations which exert bad influences on the recordingbut cannot be detected by other detecting means and other detectionmethods can be detected. Moreover, it is possible to prevent evenvibrations, which cannot exert bad influences on the recording, frombeing detected erroneously by other detecting means and other detectionmethods.

Further, since it is detected whether or not the pits are formed inactual practice, a failure of the recording due to the vibrations can bedetected. Moreover, even when the recording is failed due to anabnormality of the CD-R 10, such failure of the recording can bedetected. Therefore, it is possible to prevent a trouble in which therecording is not made normally while a user misunderstands the state ofthe recording as if the recording were made successfully.

In addition, since the recording and reproducing apparatus for recordingand reproducing the CD-R includes the function to measure the amount oflight of the reflected laser beam LREF in order to effect the focusingservo and the tracking servo upon recording, new assemblies need not beadded to this recording and reproducing apparatus. Therefore, theinfluence of the vibrations can be detected without increasing themanufacturing costs of the recording and reproducing apparatus.

Since the amount of light of the reflected laser beam LREF during theflat period τ upon recording is detected based upon the amount of lightof the reflected laser beam LREF of the flat period τ in one to severalframe periods required when the recording is started, the recording andreproducing apparatus according to the present invention can beprotected from being affected by the influences exerted by thescattering of the CD-R 10.

Further, although the recording is interrupted immediately after thecompared output signal SCMP goes to high “1” level as described above,if a track address obtained when this compared output signal SCMP goesto high “1” level is stored, then at the end of the recording, it ispossible to confirm the recorded results of the stored track addresswith ease.

While the equivalent gate circuit 31 is assumed as described above, ifthe A/D converter circuit 211 is controlled in such a manner that theA/D converter circuit 211 may convert the analog signal into the digitalsignal only during the flat period τ of the output signal SRD, then thegate circuit 31 can be omitted. While the disk on which the recordingsignal is recorded by using the laser beam is the CD-R 10 as describedabove, the present invention is not limited thereto and theabove-mentioned disk may be other suitable media such as a DVD-RAM.

[List of Abbreviations in this Specification]

-   A/D: Analog to Digital-   CD: Compact Disc-   CD-R: CD Recordable-   DVD: Digital Versatile Disc-   DVD-RAM: DVD Random Access Memory-   EFM: Eight to Fourteen Modulation-   IC: Integrated Circuit-   RF: Radio Frequency

According to the present invention, when the irradiated laser beam isnot properly focused and the tracking is displaced due to thevibrations, such defocused state and the displacement of the trackingcan be detected. In particular, even vibrations which exert a badinfluence on the recording but cannot be detected by other detectingmeans and other detection methods can be detected. Moreover, it ispossible to prevent vibrations, which cannot exert a bad influence onthe recording, from being detected erroneously by other detecting meansand other detection method.

Further, since it is detected whether or not the pits are formed inactual practice, a failure of the recording due to the vibrations can bedetected. Moreover, even when the recording is failed due to anabnormality of the disk, such failure of the recording can be detected.Therefore, it is possible to prevent a user from misunderstanding afailed recording as a successful recording.

1. In a recording apparatus for recording a signal on a disk byirradiating a laser beam on said disk, a recording apparatus comprising:a photoreceptor for receiving a reflected laser beam obtained when saidlaser beam is irradiated on said disk; a gate circuit to which a signaloutputted from said photoreceptor is supplied; a providing circuithaving an integrating circuit and a hold circuit, and being operable toreceive an output signal from the gate circuit and to provide apredetermined reference value therefrom; and a level comparing circuitfor comparing a value of the output signal from said gate circuit withthe predetermined reference value, wherein upon recording, said gatecircuit is controlled in synchronism with said signal to be recorded insuch a manner that it outputs a signal of a predetermined period fromoutput signals supplied from said photoreceptor to said gate circuit assaid output signal and an output signal of said level comparing circuitis outputted as detected results of vibrations of said disk orvibrations of a light source for outputting said laser beam.
 2. Arecording apparatus according to claim 1, wherein, said predeterminedperiod is determined based on a nearly flat period of said signaloutputted from said photoreceptor.
 3. In a recording method of recordinga signal on a disk by irradiating a laser beam on said disk, a recordingmethod comprising the steps of: receiving a reflected laser beamobtained when said laser beam is irradiated on said disk upon recordingby a photoreceptor; supplying a signal outputted from said photoreceptorto a gate circuit; supplying an output signal from the gate circuit to aproviding circuit having an integrating circuit and a hold circuit, andproviding a predetermined reference value therefrom; and comparing avalue in a predetermined period of the output signal from said gatecircuit with the predetermined reference value; and outputting thecompared result as a detected result of vibrations of said disk orvibrations of a light source for outputting said laser beam.
 4. Arecording method according to claim 3, wherein said predetermined periodis determined based on a nearly flat period of said signal outputtedfrom said photoreceptor.
 5. In a recording method of recording a signalon a disk by irradiating a laser beam on said disk, a recording methodcomprising the steps of: receiving a reflected laser beam obtained whensaid laser beam is irradiated on said disk upon recording by aphotoreceptor; comparing a value in a predetermined period out of outputsignals from said photoreceptor with a predetermined reference value;outputting the compared result as a detected result of vibrations ofsaid disk or vibrations of a light source for outputting said laserbeam; interrupting the recording when said compared result shows saidvibrations; and resuming said interrupted recording when said comparedresult shows the absence of said vibrations.
 6. In a recording method ofrecording a signal on a disk by irradiating a laser beam on said disk, arecording method comprising the steps of: receiving a reflected laserbeam obtained when said laser beam is irradiated on said disk uponrecording by a photoreceptor; comparing a value in a predeterminedperiod out of output signals from said photoreceptor with apredetermined reference value; outputting the compared result as adetected result of vibrations of said disk or vibrations of a lightsource for outputting said laser beam; storing a recording positionobtained when said compared result shows the presence of saidvibrations; and confirming the recording at said stored recordingposition when the recording is ended.
 7. A vibration detection devicefor use in a recording apparatus for recording a signal said vibrationdetection device comprising: a gate circuit to which a signal outputtedfrom a photoreceptor is supplied; a providing circuit having anintegrating circuit and a hold circuit, and being operable to receive anoutput signal from the gate circuit and to provide a predeterminedreference value therefrom; and a level comparing circuit operable tocompare a value of the output signal from said gate circuit with thepredetermined reference value, wherein upon recording, said gate circuitis controlled in synchronism with said signal to be recorded so as tooutput a signal of a predetermined period from output signals suppliedfrom said photoreceptor as said output signal and an output signal ofsaid level comparing circuit is outputted as detected results ofvibrations of said disk or vibrations of a light source for outputtingsaid laser beam.
 8. A vibration detection method for use in recording asignal on a disk by irradiating a laser beam on said disk, saidvibration detection method comprising the steps of: receiving an outputsignal representative of a reflected laser beam obtained when said laserbeam is irradiated on said disk upon recording by a photoreceptor;supplying a signal outputted from said photoreceptor to a gate circuit;supplying an output signal from the gate circuit to a providing circuithaving an integrating circuit and a hold circuit, and providing apredetermined reference value therefrom; and comparing a value in apredetermined period of the output signal with the predeterminedreference value; and outputting the compared result as a detected resultof vibrations of said disk or vibrations of a light source foroutputting said laser beam.
 9. A vibration detection device operable foruse with an optical recording apparatus having a laser, said vibrationdetection device comprising: means for receiving a signal representativeof a reflective laser beam signal having a number of pulses each havinga pulse width associated therewith and for obtaining therefrom a valueof a portion of one pulse width; means for providing a reference signalhaving a value associated therewith; and means for comparing the valueof the portion of the one pulse width and the value of the referencesignal so as to obtain a comparison result, in which the comparisonresult provides an indication of vibration.
 10. The vibration detectiondevice according to claim 9, wherein the portion of the one pulse widthis substantially flat such that the value associated therewith issubstantially constant.
 11. A vibration detection method for use inrecording of a signal on a disk by irradiating a laser beam on saiddisk, said vibration detection method comprising the steps of: receivinga signal representative of a reflective laser beam signal having anumber of pulses each having a pulse width associated therewith andobtaining therefrom a value of a portion of one pulse width; providing areference signal having a value associated therewith by use of anintegrating circuit and a hold circuit; and comparing the value of theportion of the one pulse width and the value of the reference signal soas to obtain a comparison result, in which the comparison resultprovides an indication of vibration.
 12. The vibration detection methodaccording to claim 11, wherein the portion of the one pulse width issubstantially flat such that the value associated therewith issubstantially constant.
 13. A vibration detection device operable foruse with an optical recording apparatus having a laser, said vibrationdetection device comprising: a circuit operable to receive a signalrepresentative of a reflective laser beam signal having a number ofpulses each having a pulse width associated therewith and to obtaintherefrom a value of a portion of one pulse width; a providing circuithaving an integrating circuit and a hold circuit operable to provide areference signal having a value associated therewith; and a comparingcircuit operable to compare the value of the portion of the one pulsewidth and the value of the reference signal so as to obtain a comparisonresult, in which the comparison result provides an indication ofvibration.
 14. The vibration detection device according to claim 13,wherein the portion of the one pulse width is substantially flat suchthat the value associated therewith is substantially constant.